Flooded cooling unit



June 6, 1933. Y w. E. Bxl-.IL l-:r AL

FLoonED cooLING UNIT` Filed Jan. 22. 195o 2 Sheets-Sheet l FLooDEDCOOLING UNIT Filed Jan. 22, 1930 2 sheesls'heet 2 v (ZZIIZ W v v andA172/ )fame/alf l nesg BMM-WVW Patented June 6, 1933i UNITED STATESPATENT OFFICE WILLIAM E. BIHL 'AND AXEL RAMCLAW, OF CHICAGO, ILLINOIS,SSIGNORS, BY MESNE ASSIGNMENTS, 'ro ZEROZONE'INCORPOEATED, A CORPORATIONOE DELAWARE FLOODD COOLING UNIT .Application led January 22, 1930.Serial No. 422,514.

This invention relates to flooded cooling units for mechanicalrefrigerating plants, and has for its principal object the production ofa new and improved unit of this kind.

In mechanical refrigeratning systems, such as are now being commonlyused in apartment houses, homes, restaurants, and the like, anevaporator or so-called cooling unit is installed in the refrigeratorthat is to be cooled by the system. p

Within this cooling unit is a quantity of refrigerant which iswithdrawnfrom the evaporator in the form of a vapor, and that vapor iscompressed and cooled to turn it back into liquid by a compressor unitwhich may be individual to the evaporator or common to a 7 sinceitaffords a method of lubricating the' group of evaporators. That liquidis returned to the evaporator, and this "cycle is repeated continuouslywhile the plant is in operation.

In the operation of` plants of this kind, -a certain amount of oil isemulsifed with the liquid refrigerant in the compressor and returned tothe evaporator with the liquid, where it filters out of the liquid andcollects on the surface of that liquid in the evaporator. If allowed toremain on this surface, the oil forms a blanket which greatly retardsthe evaporation of the refrigerant and consequently impairs theoperation of the system. This collection of oil on the surface'of therefrigerant in the evaporators is more pronounced in a so-calledcentralized unit system, that is one in whicha single compressor isemployed to circulate the vapor and liquid from a plurality ofvaporizers or cooling units. Installations of this kind are commonlymade in apartment houses, residential hotels, and the like.

This accumulation of oil, while it is unavoidable, is at the same timeadvantageous,

interior walls of the compressor.

This is accomplished by drawing the oil from the surface of the liquidin the evaporator through the suction pipe into the compressor, thatwithdrawal being accomplished by a skimmer connected to the pipe anddisposed in juxtaposition to the surlfface of the liquid intheevaporator unit.

on the pipe leading to the compressorunit.

This dew or frost will melt when the temperature of the pipe againrises, and the water thus collected will drop from the pipe onto thewalls ofthe building through'which the pipe runs, and damage them.

To prevent contingencies of this kind, various arrangements have beendevised heretofore, and of which we are aware, to secure a sklmming ofthe oil from the liquid refrigerant in the evaporator without danger ofpicking up some of the liquid refrigerant as well as the oil.

One of the Objects of our present invention is to provide a new andimproved skimming arrangement wherein the oil can be skimmed .from thesurface of the refrigerant in the evaporator without danger of pickingup any of the liquid refrigerant.

Evapora-tors have heretofore been usually l constructed by placing acylindrical tank in a horizont-al position and attaching a plurality ofU-shaped circulating coils to the tank. In an evaporator of the sizeused in an ordinary apartment house refrigerator, 4or 5 o f theseU-shaped coils have been attached to each side of the drum, and sinceeach of these 8 or 10 coils employed has two ends, this construction hasmade necessary the use of from 16 to 20 soldered joints in theevaporator unit, When properly `made,

these soldered joint`s"prevent the escape of refrigerant or vapor fromthe uni-t, but at the same time their presence is hazardous since, ifthe unit is jarred or ammed, the soldered joint is liable to break and aleak will result.

Furthermore, in a construction of this kind the circulating coils are ineffect in parallel with each other, so that the circula*- tion throughthem is relatively slow.V As is Well understood by those skilled in theart, the amount of evaporation of the refrigerant is a function of thetemperature of the coils, and therefore for a given temperature on theevaporator unit a given amount of vaporization takes place. Obviously ifthereare ten coils in multiple, each coil Will have a circulationthrough it equal only to one tenth of the circulation of the entiresystem, since that circulation is produced solely by the vaporization ofthe refrigerant.

This relatively slow movement of the liquid refrigerant and vaporizedrefrigerant through the circulating coils frequently results in at leastapart of those coils becoming oil-bound due to the collection of oil onthe inside surfaces of the tubes. When a tube becomes oil-bound itsrefrigerating ability is lessened and it soon becomes practicallyuseless as a medium for cooling the refrigerator.

As a further object of our present invention, We have provided a newmethod of constructing circulating coils which reduces the number ofsoldered joints necessary in the construction of an evaporator unit andalso creates a more rapid iow of liquid and vapor through thecirculating coils. This is accomplished by forming the coils in seriesrather than in parallel, so that with a given amount 'of evaporizationor vaporization of the refrigerant all of the vapor produced therebymoves through the coils in series instead of in parallel as has been thepractice heretofore. In one embodiment of our invention,

we provide two sets of series coils leading.

out of the drum so that there are but four soldered connections on thedrum instead of the sixteen or twenty that have been used heretofore.

The boiling or vaporization of the refrigerant in the coils is therebyincreased box is placed, that box being supported" on certain ones ofthe loops of the serially ref lated coils and by others of those loops.To increase the surface of the coils in thermal contact with thefreezing box, we have flattened the coils of the units so that theypresent a broad flat surface in thermal contact with the box. Thisinsures a rapid transfer of heat from the box into the lcirculatingcoils and a consequent violent boiling of the refrigerant and thereforerapid withdrawal of heat from the box.

Now -to acquaint those skilled in the art with the teachings of ourinvention, reference is here made to the accompanying drawings in whicha preferred embodimentof it is shown by Way of example, and in Figure 4is a perspective View of the float showing the details of the baiiieplate of'our skimmer arrangement; and

Figure 5 is a cross-sectional view taken along the line 5 5 of Figure 1.

Referring to the drawings in more detail, the evaporator unit comprisesthe horizontal drum 1 which is conveniently made cylindrical anddisposed with its axis in a horizontal position. The open end of thedrum 1 is rolled into the groove 2 in an end forging collar 3, this ointpreferably being also closed by silver solder or brazing to insure itstightness. The end surface 4'of the collar 3-is machined Hat and affordsa seating surface for the end plate 5 which is held thereon by bolts 6and 7. The end plate 5 may be a forging or a casting in accordance withthe usual practices vof the art. Preferably the cylindrical drum 1, thering 3 and the plate 5 are all constructed of brass, although othermaterials may be substituted therefor within the teachings of ourinvention.

On the outside end of the cover plate 5 we have located the suction linevalve 8 and the pressure line valve 9. in accordance with the usualpractice in devices of this kind.

These valves may be any valve capable of sealing ofi' the interior ofthe drum from the outside atmosphere when it is required to do so, andthe particular structure of the valves per se is not of the essence ofour invention.

Within the drum 1 we have located a float 10 which is hollow andpreferably constructed of two seamless brass cylinders fitted end to endand soldered or otherwise fastened together to make a vapor-tight joint.

A lever 11 is welded to one end of the float 10 and pivoted tothe endplate 5 by a pivot 12 suitably supported on that plate. A needle valve13, attached to the projection 14 of the lever 11, is seated in a valveseat 16 that is threaded into the end plate vand is in communicationwith the port in that plate leading to the pressure line of the'y systemthrough the valve 9. Through this arrangement, the float actuates theneedle valve 15 to seateor unseat it upon the member 16 to therebyregulate the amount of liquid refrigerant admitted to the drum 1 andcirculating system connected thereto.

A suction pipe 17 is threaded into the end plate 5 in communication withthe suction line of the system through the valve 8, that pipe containingan oil skimming projection 18 which is bent downward and terminates inthe oil film disposed upon the top of the refrigerant in the drum, aswill presently A appear.

The suction pipe 17 is bent upward and its open end disposed adjacentthe upper surface of the drum 1 in accordance with the usual practice indevices of this kind.

The compressor unit of the system, not

. shown, emulsifies a certain amount of oil with the liquid refrigerantandn that oil is returnedvto the evaporator with that liquid.

Within the evaporator this emulsified oil separates from therefrigerant.` and, being light-- y, er than the refrigerant. collects asa film 19 these devices have not completely secured the desired results.i

To aid in securing a quiet area from which the oil can be skimmed. wehave attached abaflle plate 2() to the end of the lioat 10, that bafflebeing Z-shaped. One flange of the bracket is attached to the end of thedrum and the other flange disposed on the free end of the bracketsubstantially at right angle thereto. This attachment to the drum may bemade by welding, soldering` or bazmg. or in any other preferred mannerwhich rigidly attaches the baffle to the float without 1mpairingr thevapor-tightness of the float.

The baille 2O is positioned on the drumin such a manner that itshorizontal portion lies beneath the surface of the oil and above thesurface of the refrigerant, that is. 1t lsembedded in the oil. This filmof oil frequently is a quarter of an inch thick in a commercialinstallation. so that little diiliculty 1s experienced in so locatingthe baflie 20 that its hori zontal portion will be completely' submergedin'the o il, K

As will be apparent, the positionA of the float 10 shields one end ofthe region definped by the baliie plate 20 and therefore produces aquiet area on the surface of the oil. The flange projecting from thehorizontal portion of the baiile at its free end protects the other endof this area. We have found that the refrigerant in the drum l iscomparatively quiet in the` region of the suction pipe 18,

since the majority of the boiling takes place in the opposite end of thedrum. Some boiling occurs adjacent the end plate 5 due to the ingress ofliquid refrigerant through the needle valve 15, but this is verymoderate and the'ballle plate 20 is sucient to prevent thisr boilingfrom disturbing the oil film 'around the skimmer, pipe 18.

In the preferred embodiment of our invention shown in the drawings, thecirculating pipes are led out of the back end 30 of the drum 1, anddownward therefrom through a plurality of serially related coils orloops, and return to the drum at a point in its side adjadent the endwall 30.

This arrangement concentrates the boiling of the refrigerant in theend'of the drum` farthest away from the oil skimmer, and we have foundthat the combined action of the float and baille maintain an area aroundthe skimmer'pipe 18 suiciently quiet to permit itto skim -the oil offthe refrigerant without drawing up any liquid refrigerant.

In the construction of the circulating coils, we bend a piece ofseamless tubing, preferably copper, so that it may be attached to/4 therear end 3() of the drum 1 and projected straight downward to a pointsubstantially below the lower surface of that drum. This piece of tubingis then bent at right angles to the vertical portion 31 to form a loop32 disposed in a horizontal plane beneath the drum. At the far end ofthe loop 32, which end incidentally is adjacent the vertical portion314- of the pipe, we bend the pipe at an angle of 45, as shown at 33, tobring it into a. plane located outside of the periphery ofthe drum 1.

We next form the pipe back and forth in this plane to form'la pluralityof loops 34, 35 36, 37, 38 in which the pipe is disposed horizontally,as at 39, and also a portion of it is vdisposed atan angle to thehorizontal portion, as at 40. The free end 41 of the pipe is laid alongthe side of the drum 1 and attached thereto at the point 42 adjacent theend wall 30I of that drum.

Vto

A similar series of coils or loops are formed on the opposite side ofthe drum by the pipe 43 which has one of its ends attached to the endplate 30 and the other end to the side wall of the drum adjacent thatend plate. This pipe 43 likewise has a horizontal portion 44 andvertical portion 45 which, to-

gether with the corresponding portions of the pipe 31, form a generallyrectangular box-.

to the drum with but four soldered joints in the system, whereas alarger number has been invariably used in this device heretofore.

Within the rectangular portion formed by the coiled pipe 31 and 43, weplace a freezing box 50 which is a substantially rectangular copper boxcontaining shelves 51 and 52 upon which the cube trays 53 are placed.lVhile we prefer to construct this box of sheet copper because of thebetter thermal conductivity of copper, obviously other metals may beemployed for this purpose. f1*

The box 50 is in thermal contact with the horizontal coils 32 and 44 ofthe circulating systemand also with the vertically disposed coils 34 to40, inclusive, of the pipe 31 and the corresponding coils of the pipe43. In order to increase the area of the circulating pipes in thermalcontact with the box 50, we have flattened the pipes so that a greaterarea of pipe wall is in thermal contact with the box. This flatteningoperation is preferably performed after the pipe has been bent into thedesired shape and serves not only to flatten the pipes but also toaccurately align them in planar relation to each other. All

of the coils of the two circulating pipes are thus attened so that thehorizontal coils 32 and 44 as well as the vertical coils have largeareas in thermal Contact with the bottom of the freezing box 50.

In order to conceal the valves 8 and 9 disposed on the front side of thedrum, we have provided a cover plate 60 which is supported on the drumby screws and spaced away therefrom by spacing cylinders 61 disposedaround those screws. A cover 62 disposed over the front of the freezingbox 50 is attached to the cover plate 60 by hinge 63, so that thefreezing box may be covered if desired. The addition of this cover plateand door to the front side of the box is merely for appearance sake'andin keeping with the modern practice of manufacture, and can be omittedif desired without in any way impairing the efliciency of the evaporatorunit.

ln the operation of the unit, 4suction is built up into suction pipe bythe compressor, which may be either an individual compressor or acompressor employed to operate a plurality of evaporators, that suctionwithdrawing the vapors that .have collected above the oil film in thedrum 1 through the suction pipe 17. The suction also picks up the oildisposed above the balie 20 through the oil skimmer pipe 18 and returnsthe vapor and oil vto the compressor unit. The refrigerant is returnedfrom the compressor unit as liquid through the pressure pipe and valve 9where a certain amount of it is permitted 4to enter the drum under thecontrol of needle valve 15. Within the evaporator unit itself, theliquid refrigerant flows down into. the circulating pipes, where it ismade to bo1l by the heat in those pipes. The boiling causes vapor toform, that vapor collecting in the form of bubbles which filter theirway through the liquid in the pipes into the drum 1 and thence upthrough the liquid and oil heat absorber and transfers the heatabsorbed.

to the refrigerant to boil it. The vapor produced in each coil of thecirculating pipe is added to that produced in the other coils, 'so thatthe boiling produced in the coils is violent, and the circulation of theliquid refrigerant through these coils is therefore I rapid.

This rapid circulation of the refrigerant prevents the accumulation of afilm of oil on the inside surface of the circulating pipes and thereforemaintains the circulating system in condition to efficiently transferheat.

from the refrigerator to the liquid refrig- Herant in the pipes.

lnasmuch as the sections 40 of the circulating pipes slope downwardlyand the gas in those sections must therefore flow downward, it mightappear that a trap would be formed and the circulating system becomegas-bound. However, We have found that the boiling is so rapid in thepipes that the gas flows freely through them even though it flowsdownward through a part of its travel, and in a commercial installationof the evaporator shown in the drawings, successful operation has beencarried on over a long period of time without the box becoming eithergasbound or oil-bound.

Since the outlet and inlet portions leading from the drum into thecirculating pipes are both located adjacent the end 30 of thev drum 1,the eater part of the boiling of the liquid refrigerant in the drumtakes place at that end which is remotely removed from the skimmer pipe18. Skimming oil 0E of the refrigerant without drawing up liquidrefrigerant is facilitated by the combined action of the float, thebaflie, and the concentration of the boiling in the back end of the drumto produce a quiet area around the skimmer pipe through which the oilcan be skimmed.

While We have chosen to show our invention by illustrating a preferredembodiment, we have done so by way of example only, as there are manymodifications and adaptations which can be made by one skilled in theart within the teachings of the invention. We are therefore to belimited only by the appended claims.

I What we claim is 1. In a refrigerating unit, an evaporatorcomprisingaJ closed horizontally disposed drum, a circulating pipeleading out of one end of the drum downward through a horizontal coildisposed beneath the drum, thence upward to said drum through aplurality of serially relatedl substantially horizontal pipes arrangedone above the other in a vertical plane, a second circulating pipeextending through a second series of serially related substantiallyhorizontal coils, a metallic freezing box resting on the horizontalcoils and between the pipes of the two series ,`and a means within saidbox for holding ice cube trays. l

2. In a refrigerating unit, an evaporator comprising a closedhorizontally disposed drum, acirculating pipe leading out of one end ofthe drum downward through a horrzontal coil disposed beneath the drum,thence upward t said drum through a plurality of serially relatedsubstantially horizontal pipes arranged one above another in a verticalplane, a second circulatingfpipe extending through a second series oserially related lorizontal rcoils and pipes, a metallic Vfreezing boxresting on the horizontal coils and between the substantially horizontalpipes of the two series, and a cover plate fastened to the other end ofsaid drum and v supporting a door lfor said box.

3. In a refrigerating unit, an evaporator comprising a closedhorizontally disposed drum, a circulating pipe havingits two endsattached to said drum near one of its ends, said pipe being formed intofa plurality of serially related coils extending from one end of the drumto the other, one of said coils being disposed in a horizontal planebelow saidV drum, and the other ones of said coils being disposed oneabove the other in a vertical plane alongside said drum, a secondcirculating pipe similarly attached to said drum and similarly formedinto coils one of which also lies in said horizontal plane, a freezingbox resting on said planar coils and between said other coils, and meansin said box for holding ice trays. 4. In a refrigerating unit, anevaporator comprising a closed horizontally disposed drum, a circulatingpipe having its two ends attached to said drum near one of its ends,said pipe being formed into a plurality of serially related coilsextending from one end of the drum to the other, one of said coils beingdisposed in a horizontal planebelow said drum, and the other ones ofsaid coils being disposed one above the other in a verticalplanealongside said drum, a second circulating pipe similarly attached tosaid drum and similarly formed into coils one of"which also lies in saidhorizontal plane, and a rectangular freezing box resting on said planarcoils between said `other coils. h

5. In a refrigerating unit, an evaporator unit consisting of ahorizontally disposed closed drum, a circulating pipe extending downwardfrom an opening in one end of the drum through a horizontal loopdisposed beneath the drum thence through a plurality of loops disposedin a vertical plane which is parallel to the axis of said drum andlocated outside its periphery, thence back into the drum through anopening disposed in its side adjacent said end, a second circulatingpipe extending from a second opening in the end of the drum seriallythrough a pluralityfof `coils disposed ina similar manner to the firstbut on the opposite side of the drum through in one side of said drumadjacent said other f end and leading out of thevlast one of said coilsinto said drum. 7 .'In a refrigerating unit, an evaporator r\comprisinga horizontally disposed closed drum having refrigerant inlet and outletports located in one end thereof, a plurality of substantiallyhorizontal serially related circulating coils, disposed in a verticalplane beneath said drum, a port disposed in the other end of said drumand leading into the first one of said coils, and a second port disposedin one side of said drum adjacent said other end and leading out of thelast one of said coils into said drum.

8. In a refrigerating unit, an evaporator comprising a horizontallydisposed closed drum, a circulating pipe leading from one end of saiddrum vertically downward to a point beneath the drum, horizontally in ahorizontal plane through that point and equidistant from the bottom ofthe drum to a point below the opposite end of the drum, back inthatplane to a point adjacent said first point, upward therefrom to aplane disposed at right angles to thelirst plane and outward of saiddrum, back and forth in that plane from one end of the drunr to theother, and back into said drum at a point in its side adjacent said end,and a liquid in said drum covering the ends of saidpifpe.

9. In a refrigerating unit, a closed drum having refrigerant'inletandoutlet ports located in one end thereof, a pair of circulating pipeseach leading out of a side wall of said drum adjacent the opposite endthereof and extending throughl a plurality of serially related coils,the last coil of each of said pipes kbeing disposed in al horizontalplane and .y

opening dinto the opposite end of said drum,

a freezing box resting on said horizontal coils,

comprising a horizontal sealed drum, a pair of circulating pipes leadingout of an end of the drum and back into it through its sides at pointsadjacent said end, an inlet port disposed in the opposite end of saiddrum, a float pivoted to said drum adjacent said inlet port, an outletport also disposed in said opposite end, a liquid filling said pipes anddrum to a height regulated bysaid oat, and

y'means including a baiile mounted on said iioat and disposed a fixeddistance below the surface of said liquid, and a skimming pipe extendingfrom said inlet port to a point adj acent said batlie for skimming saidliquid.

11. In a refrigerating unit, the combination with a closed tankcontaining liquid which has a lm of oil over its upper surface, a floatfor regulating the height of that liquid and oil, and a suction pipe formaintaining the remainder of the tank at a low pressure, of a baffleplate attached to the end of the float and having a substantiallyhorizontal portion disposed above said liquid surface in said oil lm,and a skimmer pipe tapped out of said suction pipe and extending to theupper surface of said baiiie to skim the oil therefrom.

comprising a closed tank, an inlet port disposed in one end thereof, alever pivoted to that end of the tank, a needle valve connected to saidlever and operated in and out of said port thereby, a float connected tothe free end of said lever, a Z-shaped baile plate disposed with isdownward depending iange attached to the float above said lever and itsfree ange extending upward substantially parallel to the end of theiioat, a suction pipe projecting through said end above said inlet portand opening upward above said float, and a pipe leading from saidsuction pipe to a point between the free end flange of said baille andthe end of said float and above said baiie.

In witness whereof, we hereunto subscribe our names this 17 day of Jan.,1930.

WILLIAM E. BIHL. AXEL RAMCLAVV` posed in one end thereof, a leverpivoted to that end of the tank, a lever valve connected to said leverand operated in and out of said port thereby, a oat connected to thefree end of said lever, a baiile plate connected to said float abovesaid lever, and a suction pipe terminating above said baiiie injuxtaposition thereto.

13. In a refrigerating unit, an evaporator comprising a closed tank, aninlet portdisposed in one end thereof, a lever pivoted to that. end ofthe tank, a needle valve connected to said lever and operated in and outof said port thereby, a iioat connected to the free end of said lever, aflanged baiie plate connected to said ioat above said lever, and asuction pipe terminating above said baille in juxtaposition thereto.

14. In a refrigerating unit, an evaporatorl comprising a closed tank, aninlet port disposed in one end thereof, a lever pivoted to that end ofthe tank, a needle valve Connected to said lever and operated in and outof said port thereby, a float connected to the free end of said lever, aZ-shaped baiiie plate dis# posed with its downward depending flangeattached to the oat above said lever and its free Harige extendingupward substantially parallel to the end of the iioat, and a suctionpipe terminating above said baiie in juxtaposition thereto.

15.- In a refrigerating unit, an evaporator comprising a closed tank, aninlet port dis-

